MIAMI, Florida (CNN) -- More than a million people who want to vote in November's general election probably won't get the chance because of a delay in processing applications to become U.S. citizens, according to the U.S. Bureau of Citizenship and Immigration Services.

A backlog processing naturalization applications could keep over a million immigrants from voting this fall.

The dream of voting in the upcoming presidential election -- along with a scheduled increase in fees -- motivated 1.4 million people across the country to apply after June 1 last year to become naturalized U.S. citizens -- double the previous year's number, the bureau said.

The huge jump in applications also increased the time normally needed to process them from about seven months to as many as 18 months.

Serena Perez moved to the United States from Ecuador more than 10 years ago after marrying an American citizen. She applied for citizenship in May, thinking she would have plenty of time to become a citizen and be granted the right to vote. But now, she probably won't get that chance. Watch how the backlog affects voting »

"What is the reason for this backlog when there are so many people in an election year that are willing to participate?" Perez asked.

Immigrant advocate Jose Lagos is furious at the slowdown.

"They say they are doing what they can, but we think they can do more," Lagos told CNN.

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At a recent congressional hearing, the U.S. Bureau of Citizenship and Immigration Services said it's hiring 1,500 more employees to handle the delays. But officials say that even with the additional resources, there's little chance the backlog will be significantly reduced by the November election.

Immigrant rights groups estimate as many as 200,000 legal residents in Florida alone are waiting to learn if they'll become citizens in time to vote. And in Florida, where the results of the 2000 election hung in the balance, thousands of new voters could swing the 2008 vote.

Historically, Florida immigrants -- many of them Cubans -- tended to vote Republican. But as more apply for citizenship from other countries, experts say, the immigrant vote is now up for grabs.

Mitch Ceasar, a Democratic party chairman in South Florida, says there are suspicions about the delay.

"Conspiracy theorists may say this is grinding to a very slow movement or halt specifically to disenfranchise these new legal citizens from finishing their process and becoming voters," Ceasar said.

That view is dismissed by Jose Riesco, the Republican party vice chairman in Miami-Dade County.

"We don't have voter suppression here," Riesco said. "That is ludicrous. It is an election year, and that is political rhetoric."

Either way, Perez thinks her vote could make a difference.

"I'm going to feel I'm missing an opportunity to change the way the government is running this country. ... And I really feel that I want to be able to be part of that change," Perez said. E-mail to a friend